Technical Field
The present disclosure relates to antenna assemblies for electromagnetic navigation and methods for designing such antenna assemblies. More particularly, the present disclosure relates to antenna assemblies for radiating electromagnetic fields for electromagnetic navigation, electromagnetic navigation systems including such antenna assemblies, and computer-implemented methods of designing such antenna assemblies.
Discussion of Related Art
Electromagnetic (EM) navigation (EMN) has helped expand medical imaging, diagnosis, prognosis, and treatment capabilities by enabling a location and/or an orientation of a medical device to be accurately determined while the device is within the body of a patient. One example of a medical procedure in which EMN is employed is ELECTROMAGNETIC NAVIGATION BRONCHOSCOPY® (ENB™), which includes a planning phase and a navigation phase. During the planning phase, a computed tomography (CT) scan of the chest of the patient is used to generate a virtual three-dimensional bronchial map of the patient and a planned pathway for the navigation phase. During the navigation phase, an antenna assembly radiates an electromagnetic field throughout the chest of the patient, a practitioner inserts into the airway of the patient an electromagnetic sensor that senses the radiated electromagnetic field, and a computing device determines a location and/or an orientation (e.g., relative to the planned pathway) of the electromagnetic sensor based on characteristics of the sensed electromagnetic field.
To enable accurate determination of sensor location and/or orientation, a detailed mapping of electromagnetic field measurements at respective sensor locations is generated. Generating such a mapping, however, requires taking precise electromagnetic field measurements at many (for example, hundreds of thousands or more) locations within the expected electromagnetic volume, which is a laborious and time-consuming process that, in some cases, requires expensive machines.
The burden of generating electromagnetic field mappings increases in circumstances where multiple antenna assemblies are employed. For example, in order to enable an electromagnetic sensor to reach deeper portions of the body of the patient, and/or remain within the body during subsequent medical procedures without interfering with additional medical devices, it may be desirable to employ a small electromagnetic sensor, such as a single-coil electromagnetic sensor. However, to employ a small electromagnetic sensor for EMN while maintaining the ability to determine multiple (for example, six) degrees of freedom of the sensor, multiple antenna assemblies may be required to increase the number of radiated electromagnetic fields to be sensed. In such a case, the above-noted exhaustive mapping procedure may need to be conducted for each antenna assembly design. Moreover, given potential variations from manufacturing, the mapping procedure may even need to be completed for each instance of a specific antenna assembly design (i.e., each individual antenna assembly manufactured).
Given the foregoing, a need exists for improved electromagnetic navigation antenna assemblies and methods for designing such antenna assemblies.